A group of Medford neighbors is mounting an effort to save a venerable beech tree they fear could be chopped down as a part of a development project.

The towering beech — which members of the group estimate to be more than 200 years old — sits on a site at 23 Walnut St., where a developer plans to build a duplex.

The firm, Walnut Crossing LLC, is renovating a 19th-century home into three condominium units to the rear of the property.

“It’s just an amazingly beautiful old tree,’’ said Sheila Cataldo, who lives down the street “There aren’t any of them around anymore, and this is just a particularly huge, beautiful tree.’’

Sharon Guzik, another nearby resident, said concerns the tree could be cut down have spurred 190 residents to sign a petitionto be sent to the developer asking it be spared.

Guzik said many comments have been posted about the tree on a Facebook page.

Guzik praised Walnut Crossing LLC for the work it has done to restore the adjacent home, which she toured recently with Scot Kenworthy, owner of the firm. But she said if the tree goes, it would be a major loss.

The developer has the legal right to remove the tree, but “we are going on our knees and pleading with him not to damage it or cut it down,’’ Guzik said.

In an interview, Kenworthy said he cannot commit to preserving the tree but is doing what he can to save it. He said that involves working with an engineer and an arborist to determine the location of the root system and whether those roots would be in the way of the planned duplex.

“People should reserve judgment and let me continue to do what I have been doing . . . to save the tree,’’ said Kenworthy, a Melrose resident whose maternal grandparents were from Medford.

“I’m the only guy who has been preserving historic houses in Medford,’’ Kenworthy said, citing a similar project he undertook nearby on South Street. “I could have knocked the [Walnut Street] house down. . . . And if I didn’t care about the tree, I would have cut it down on day one.

“I love that tree,’’ he said, noting that he used to come by to eat his lunch next to the tree while he was working on the South Street project. “It’s awesome. That’s why it’s still standing.’’

John Laidler can be reached at laidler@globe.com.